This disclosure relates to a demand supply response associated with an appliance, and particularly a refrigerated appliance where operation of the refrigerated appliance may be altered in response to a high demand for energy and peak pricing. Selected aspects may find use in related applications.
It is well known that refrigerators have two or more compartments for storing food items, that is, at least one freezer compartment and at least one fresh food compartment. The locations of the separate compartments may vary. For example, in a bottom mount refrigerator the freezer is located on the bottom and the fresh food compartment is on top, while in a top mount arrangement, the compartments are reversed. In a side-by-side arrangement one side is the freezer compartment and the other side is the fresh food compartment. In still another style, the fresh food compartment includes side-by-side doors and the freezer compartment is located on the bottom. No matter which style is employed, these compartments are divided one from the other by one or more walls that are thermally insulated in order to maintain the temperature in the freezer compartment at, for example, about 0° F. and in the fresh food compartment at approximately 37° F. Of course, these are exemplary temperature ranges only.
Gaskets are provided to seal around access openings to these compartments and the gaskets extend from peripheral regions of doors that close the access openings to the respective compartment. The gaskets sealingly contact a generally planar, perimeter surface of the housing or case that surrounds the access opening when the doors are closed. Thus, the metal or housing surface is exposed to 0° F. air from the freezer compartment, for example, along one edge of the gasket and exposed to ambient air (about 68° F.) associated with the room along another edge of the gasket. Since the metal housing is thermally conductive, a portion of this metal surface (sometimes referred to as a mullion bar), or specifically that housing area between a pair of gaskets, conducts the heat in and conducts the cold out. As a result, a gap region of the housing between the gaskets or adjacent the gaskets is exposed to ambient air and can be at a temperature below the dew point temperature. Fog or moisture can form beads of sweat in this mullion region and the beads can coalesce to form water droplets that potentially reach the floor.
To prevent the formation of moisture or sweat in these regions, a heater such as a low wattage electric resistance heater is typically employed. This heater(s) is sometimes referred to as an anti-sweat or mullion heater. One type of these heaters operates on approximately 8 to 12 watts and is preferably a fine nichrome wire heater wrapped in and insulated by a surrounding vinyl sheathing. The wire is disposed on a cloth carrier that is attached to an adhesive backed foil. These small resistance-type heaters are usually secured to or provided in those areas of the refrigerator where sweat is likely to collect, for example along edges of the door, case flange, mullion, etc.
In a side-by-side refrigerator, the gaskets of the side-by-side doors form a generally vertically extending channel therebetween which can contribute to potential water drippage through the channel. Understandably, water dripping on the floor adjacent the refrigerator is undesirable and thus the anti-sweat heaters are used to raise the temperature in these regions above the dew point.
In response to utility companies beginning to charge higher rates during peak demand periods, there is a desire to control or reduce energy use by appliances which also results in a potential cost savings for the consumer/homeowner. Various responses have been proposed for different appliances, including refrigerators, when higher rates are being charged during peak demand periods. Generally speaking, inactivating or disabling anti-sweat heaters is sometimes avoided as a viable demand response option during peak pricing because of the potential concern that moisture or water could reach the floor. It is recognized that peak pricing periods could last two to four hours or more and, in this time frame, there is the possibility that sweat could develop in such regions. Therefore, because there is a concern about sweat developing on the mullion bar during an extended high or critical rate (particularly in high humidity environments) and that such sweat formation will possibly be exacerbated because the home air conditioning will also be concurrently “controlled” to a condition that will produce increased humidity in the conditioned space, the anti-sweat heaters are typically left operational during peak demand periods. Moreover, 8-12 watts is deemed to be a relatively small energy value and thus proposed demand responses have focused on other energy and cost saving areas that could result in a greater energy savings.
Consequently, a need exists for providing a demand response that addresses the anti-sweat heaters and the potential energy and cost savings associated therewith.